首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1567篇
  免费   106篇
  国内免费   12篇
耳鼻咽喉   27篇
儿科学   31篇
妇产科学   23篇
基础医学   256篇
口腔科学   36篇
临床医学   89篇
内科学   398篇
皮肤病学   43篇
神经病学   145篇
特种医学   38篇
外科学   202篇
综合类   8篇
预防医学   70篇
眼科学   49篇
药学   117篇
中国医学   10篇
肿瘤学   143篇
  2024年   2篇
  2023年   21篇
  2022年   55篇
  2021年   89篇
  2020年   49篇
  2019年   52篇
  2018年   58篇
  2017年   45篇
  2016年   52篇
  2015年   43篇
  2014年   64篇
  2013年   82篇
  2012年   148篇
  2011年   128篇
  2010年   83篇
  2009年   39篇
  2008年   112篇
  2007年   74篇
  2006年   92篇
  2005年   97篇
  2004年   83篇
  2003年   69篇
  2002年   69篇
  2001年   12篇
  2000年   12篇
  1999年   4篇
  1998年   8篇
  1997年   8篇
  1996年   8篇
  1995年   5篇
  1994年   1篇
  1993年   6篇
  1992年   3篇
  1990年   4篇
  1989年   2篇
  1988年   3篇
  1985年   1篇
  1983年   1篇
  1964年   1篇
排序方式: 共有1685条查询结果,搜索用时 0 毫秒
131.
To improve the quality of life of elderly people in Japanese society where women have the longest life expectancy in the world, osteoporosis, and hyperlipidemia are among the major targets of medical treatment. To differentiate two types of regimens for hormone replacement therapy (HRT), we tried to evaluate the efficacy on lipid and bone metabolism. With informed consent, 34 postmenopausal women of more than 2 years were assigned to receive 1 of 2 types of HRT (the HRT group) for 12 months observation: one with a combination of conjugated equine estrogen (CEE) 0.625 mg/day and medroxyprogesterone acetate (MPA) 2.5 mg/day (the CEE group), and the other with oral estriol (E3) 2 mg/day (the E3 group). Parameters of serum lipid were measured, as well as those of bone metabolism with bone mineral density (BMD) by dual-energy X-ray absorptiometry (DEXA) using QDR-2000. In HRT groups, lipid and bone metabolism were confirmed to be improved. Whereas, an increase of triglycerides (TG) observed in the CEE group was not observed in the E3 group. Thus, in the clinical management of postmenopausal women, oral E3 preparation as an alternative regimen for HRT for CEE might be efficacious.  相似文献   
132.
Several studies suggested that the activity of erythrocyte Na,K-ATPase declines with aging. Here, it is postulated that alterations in the substrate kinetics of the erythrocyte membrane Na,K-ATPase could be more aggravated in conditions of brain cholinergic dysfunction seen in Alzheimer's disease than in normal aging. To test this hypothesis, we compared the Na,K-ATPase activity (Vmax/Km parameters) in aged rats with those in young rats with brain cholinergic dysfunction induced by electrolytic-, kainic acid-lesioned nucleus basalis magnocellularis (NBM) or by intracerebroventricular AlCl_{3} administration. In the above mentioned groups, Vmax values were significantly lower in comparison to the control animals. Furthermore, Km values were significantly higher in animals with electrolytic-induced NBM lesions, AlCl_{3} treated rats and aged animals. However, Km was significantly lower in kainic acid-induced NBM lesions compared to the control group. The Na,K-ATPase catalytic efficiency, estimated by the ratio Vm/Km, decreased as followed: young animals > aged animals > kainic acid lesion > electrolityc lesion > AlCl_{3}. Our data suggest that neurodegenerative processes similar to those seen in Alzheimer's disease affect the sodium/potassium pump functionality which might be detected in peripheral blood erythrocyte membranes.  相似文献   
133.
Abstract:  Since first being described in 1998, de novo autoimmune hepatitis (AIH) after liver transplantation has been reported in several cases suffering from non-autoimmune liver diseases and primary biliary cirrhosis (PBC). Glutathione S-transferase (GST) T1 genotype mismatches between donor and recipient have also been suggested to constitute a risk factor for de novo AIH. Here, we report a 33-yr-old woman who presented complaining of marked fatigue and jaundice four yr after living-donor liver transplantation for PBC. On examination, transaminase levels were highly elevated and ANA and antimitochondrial antibody M2 were positive. Histological findings showed zonal necrosis with lymphoplasmacytic infiltration closely resembling AIH. She had pretreatment AIH score of 16 and 19 points after relapse of de novo AIH. Two color fluorescence in situ hybridization with X and Y chromosome-specific probes clearly revealed that the hepatocytes were of donor origin and lymphocytes were of patient origin. The GSTT1 genotype of the patient and the donor were the same null type, suggesting that mechanisms other than GSTT1 mismatches may exist in de novo AIH development. In conclusion, recipient immune cells attacked the allogeneic transplanted liver of the patient via de novo AIH, although the exact participation of autoimmune mechanisms is unclear.  相似文献   
134.
Nephronophthisis (NPHP) is a disease characterized by a genetic cause of chronic renal failure in children and adolescents, complicated with several extra-renal manifestations such as retinal defect and/or liver fibrosis. Although it is difficult to establish the correct diagnosis, mutations in six genes (NPHP 1-6) have recently been identified. Here we report the case of a 25-year-old male with NPHP with congenital hepatic fibrosis. He showed microscopic hematuria and moderate proteinuria at 20 years. Renal biopsy revealed severe interstitial fibrosis, diffuse tubular atrophy and microcysts at this time with chronic kidney disease stage III (Cr 2.43 mg/dl). C3c was positive in glomeruli in direct immunofluorescent study. Although his mother belongs to a family with polycystic kidney disease, he did not have a novel genetic background of Arg585Cys mutation in exon 8 of the PKD1 gene. Magnetic resonance angiography (MRA) showed typical portal hypertension with spleno-renal shunt caused by biopsy-proven liver fibrosis. Thus, we diagnosed him as having undetermined renal cystic or tubulo-interstitial disease complicated with membranoproliferative glomerulonephritis (MPGN). Renal transplantation was performed in January 2005 after 2 years of dialysis therapy. He was transported to our emergency room because of severe abdominal pain in December 2005. A computed tomographic scan showed massive ascites, which were caused by rupture of the splenic artery. Despite full intensive care including intraluminal coiling of the ruptured aneurysm and extensive blood transfusion, we failed to rescue him on the next day. The autopsy findings revealed severe atrophy of the bilateral kidney with multiple cysts along the cortico-medullary border. Obvious portal hypertension, resulting from congenital hepatic fibrosis, could account for the rupture of the splenic artery with aneurysm formation under pressure/volume overload. This is the first report of a NPHP patient with the complication of hepatic fibrosis emerging from an ADPKD family. As it remains elusive on the phenotype–genotype of the Japanese NPHP population, a registration system of cystic disease of the kidney is required.  相似文献   
135.
BACKGROUND: In Japan, systematic evaluation of the histologic parameters of anti-neutrophil cytoplasmic autoantibodies (ANCA)-related vasculitis has been performed according to the Japanese classification by Shigematsu et al. However, this classification is quite different from that of the European Vasculitis Study Group (EUVAS) classification. Therefore, a histological common basis is needed to compare Japanese histological data with the international database. METHOD: Histological parameters concerning glomerular, tubulointerstitial, and vascular lesions of ANCA-related vasculitis, which are indispensable for clinical management, were elucidated and defined by reviewing, utilizing the merits of, and amending the two scoring systems. RESULTS AND CONCLUSION: A new comprehensive and standardized scoring system, by which histological quantitative assessment can provide evidence for therapy planning, has been developed for renal biopsy of Japanese ANCA-related vasculitis.  相似文献   
136.
137.
Mitral regurgitation due to papillary muscle rupture after blunt chest trauma is uncommon. Sudden onset severe mitral regurgitation may lead to death due to heart failure if surgical repair is delayed. A previously healthy 12-year-old girl underwent splenectomy and chest tube insertion for pneumothorax after a traffic accident in a vehicle 15 days before. She was discharged from the hospital after a nine-day follow-up. She was presented to our hospital due to respiratory distress. On physical examination, an apical holosystolic murmur radiating to the axillary region was recognized. Transthoracic echocardiogram showed severe mitral regurgitation with freely moving posterior mitral chordae and prolapse of the posterior mitral valve leaflet. She received reimplantation of the complete ruptured posteromedial papillary muscle of the mitral valve. Her medical condition improved after the operation. On the postoperative echocardiogram, the left ventricular systolic function was normal with no mitral regurgitation.  相似文献   
138.
Two 20-membered macrolides, iriomoteolides-1b ( 1) and -1c ( 2), have been isolated from a marine dinoflagellate Amphidinium sp. (strain HYA024), and the structures were elucidated on the basis of detailed analyses of 2D NMR data and chemical correlation.  相似文献   
139.
140.
Although the presence of renal cysts has been reported to be associated with aortic aneurysm or dissection by imaging studies, an autopsy study has not been performed. Therefore, in our institute, recent consecutive adult autopsy cases (n = 108, 64 males and 44 females) were reviewed. The circumferences and atherosclerosis ratios of both thoracic and abdominal aorta were individually measured and graded. The number of renal cysts was scored and graded. Age of subjects along with histories of smoking, hypertension, and diabetes mellitus were confirmed. Multiple linear regression analyses demonstrated that severity of atherosclerosis and the number of renal cysts were correlated with thoracic aortic circumference, while only the number of renal cysts was correlated with abdominal aortic circumference (p < 0.05), which was more predominant in female subjects (p < 0.05). Microscopically, significantly more dilated renal tubules (by Student's t-test, p < 0.05) along with decreased stainability of basement membrane by Periodic acid-Schiff staining and immunostaining of type IV collagen were noted in background renal tissues in cases with numerous renal cysts than in age- and sex-matched controls without renal cysts (n = 10 vs. 10). The present study suggests that a syndrome that affects both aorta and renal tubules may exist.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号